Accessing a network using a wireless connection has gained in popularity in recent years due to its convenience. One approach for accessing a network using a wireless connection is described in the IEEE 802.11 specification. According to this approach, a client transmits a probe request to one or more access points that are within range of the client. An access point (AP) is a component that is configured to provide wireless service to one or more clients. A typical network may have many access points. A probe request is a message sent from a client to an access point to determine if the access point is able to provide service to the client.
After an access point receives a probe request, the access point transmits a probe response to the client. The probe response indicates that the access point sending the probe response to able to provide service to the receiving client.
As a client will typically transmit a probe request to more than one access point, a client will typically receive more than one probe response in return. Each client follows a procedure to determine which access point from which the client should attempt to request service. For example, a client may determine which access point the client should attempt to request service from based on which access point transmitted a probe response with the strongest signal. By connecting to the access point that sent the probe response with the strongest signal, the client improves the likelihood of receiving quality service from an access point.
After a client selects a particular access point from which to receive service, the client transmits a request for service to the particular access point. Thereafter, the particular access point provides service to the client.
Each access point may have a limit on the number of clients that the access point can service. For example, as more clients connect to a particular access point, the demands on the resources of the access point increase. At some point, the access point may not be able to service an additional client without degrading the quality of service provided to clients from that access point to an unacceptable level. Consequently, an access point may deny service to a particular client requesting service if the demands on the resources of the access point exceed an acceptable level.
In order to accommodate as many clients as possible, the designers of a wireless network determine the number and location of access points based on a predicated number and location of clients. For example, the number and location of access points for a company may be determined by estimating the number of clients in a physical location (e.g., a building, floor, or office complex). In such cases, determining the average number of clients per access point can be easily predicted as the number and location of the clients is known.
There are situations, however, when it is difficult to predetermine how many clients will need access to the network. For example, it is difficult to determine how many clients will need access during conventions, press conferences, hot-spots, and other non-regular events. In such situations, a client may not be able to gain access to the network because the demand on the available access points in that location is too great. This problem is especially troublesome if the client requesting wireless access has a special need for access, e.g., the client may be involved in a presentation during the convention in which wireless access is required.
Further, even if additional access points are added to a physical location for a non-regular event, such as a convention, clients may still not be able to obtain the service they require. As clients typically employ the same or similar procedure to determine from which access point to request service, it is possible that even if a number of access points are added to support a particular location, each client in that location may still attempt to request service from the same access point, e.g., each client will attempt to request service from the access point that responds to a probe request with the strongest signal. Thus, the majority of clients at the same location will attempt to request service from a single access point, even if other access points are available. This access point will eventually get overloaded with requests from clients, causing service provided by that access point to degrade in quality. Further, as clients typically employ the same or similar procedure to determine from which access point to request service, every client that is denied service from one access point will likely attempt to connect to a second access node, which may exceed the capabilities of the second access node as well.
Consequently, an approach for providing load balanced wireless access to a network, without incurring the disadvantages of prior approaches, is desirable. The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.